This invention relates to digital computer programming systems and, more specifically, to a method for conversion of software to operate in a systems environment foreign to that from which it originated.
The rapid growth of the computer hardware industry in the United States has placed on the market a wide variety of programmable digital computers at all price levels. The market for these machines has expanded rapidly because technological advances have caused the price of computing power to fall by a factor of 1,000 within the past decade. Thus, digital computers today are being applied to a far wider variety of tasks than before, including many tasks which, ten years ago, were more economical to perform by hand.
The proliferation of computers has resulted in a shortage of personnel trained to program these systems. This is reflected in the well-known high salaries currently offered to experienced programmers. Moreover, while organizations such as the American National Standards Institute (ANSI) have promoted programming language standards for use on all systems, most manufacturers produce a superset of the applicable ANSI standard language which amounts to a dialect applicable only to systems produced by that manufacturer. As a result, programmers who become familiar with one system and its dialect must spend substantial time learning a second dialect when writing software for a different system.
Also due to differences in dialect, software which has been written and debugged to run on a given machine will seldom, if ever, perform the same functions without error on a different machine. Timing constraints, file conventions, memory allocations and input-output control addresses, as well as other factors, all may be reflected in the text of a given software product. When attempting to modify software to operate on a system other than that from which it originated, failure to properly adjust these factors may cause not only loss of the software itself but also erasure of other files and peripheral storage.
As the shortage of programmers has become more widely recognized, and the libraries of useable software for particular systems have expanded, the need has arisen to convert software from one system to operate on a different system. This would allow programmer efforts to be directed to new developments rather than redevelopment of already-existing software. Generally speaking, however, where conversion has been attempted, it has required the effort of a programmer familiar with both the system from which the software originated and the system to which it is being converted. As noted above, such personnel are difficult to locate and command premium salaries. Therefore, there remains an uneconomical duplication and waste of scarce programming resources to produce software performing identical functions on different systems.